Apparatus for a roll-to-plate embossing process comprising a printing plate carrier having cavities

Abstract

The present invention relates to an embossing device for a roll-to-plate process, the embossing device comprising a flexible master with an embossing pattern, a plate carrier and a substrate and a curable embossing resin. The substrate is located on the plate carrier. The flexible master carries an inverted structure (embossing pattern), which is required for the desired product. The curable resin (also called lacquer) is placed on the substrate and / or the flexible master. During the embossing process, the flexible master is pressed against the substrate with the curable resin located therebetween. The plate carrier comprises a cavity in which the substrate is located. At least one substrate side is at least partially not surrounded by the cavity. Another idea of ​​the present invention relates to two roll-to-plate embossing processes.

Description

Technical Field

[0001] The present invention relates to an embossing device for a roll-to-plate process. Background Art

[0002] Imprinting equipment for the roll-to-plate process is known and comprises a roller, a flexible master with an imprint pattern, a plate carrier and a substrate and a curable imprint resin. The substrate is located on a carrier material. The flexible master carries a reverse structure (imprint pattern), which is necessary for the desired product. The curable resin (also called lacquer) is placed on the substrate and / or the flexible master. During the imprinting process, the flexible master is pressed against the substrate using a roller, with the curable resin located therebetween. After curing, the resin is cured, for example by heating and / or ultraviolet rays, and the flexible master is removed, thereby producing a textured region on the substrate.

[0003] For example, known prior art for a roll-to-plate embossing apparatus is described in WO 2016128493.

[0004] In document US 2016 / 257062, an imprinting device is disclosed in which a flexible mold is held on a surrounding platform by a vacuum and pressed against a substrate containing a curable resin (see Figure 1 ) to achieve uniform transfer regardless of the thickness of the substrate. The document also discloses a plate on the platform, which forms a cavity.

[0005] JP 2016 197672 discloses an imprinting device and an imprinting method for preventing resin flow. A substrate is positioned on a platform, whereby an elastic member is arranged on the platform to form a gap portion. The gap portion should surround the substrate and be Figure 1 , the substrate is embedded in the elastic material (forming an elastic member around the substrate).

[0006] The imprint quality and the residual layer thickness of the textured area on the substrate depend on process settings such as imprint speed and imprint pressure. In order to obtain a thin residual layer, a higher imprint pressure is applied on the roller. This imprint pressure is applied on both sides of the roller. Achieving a uniform imprint pressure over the entire imprinted substrate area is complicated by the discontinuity of the process and having a line pressure. The non-uniform pressure of the roller will affect the pressure of the flexible master on the curable material of the substrate and lead to variations in the properties of the obtainable product. For wafer-level imprint processes, this uniformity issue is solved by full-surface imprinting or varying and well-controlled pressure over the imprint area using a flat substrate and a mask holder (chuck). The roll-to-roll replication process is a continuous process on a square surface.

[0007] Specifically, there are two main process conditions that lead to uneven pressure.

[0008] -After placing the substrate on the carrier, the roller will have transition areas at the first and last contact points of the substrate. The roller pressure will be applied and distributed to the lower carrier surface and the upper substrate surface. Therefore, the imprint pressure will be higher at the start and end of the substrate, especially for thicker substrates.

[0009] - If the substrate has a varying width, the line pressure per unit area of ​​the embossing roller will vary on the substrate. Due to the varying width, the same line pressure will be applied over a wider or smaller area.

[0010] Therefore, by using such a roller-to-plate apparatus, it is generally difficult to apply uniform pressure over the entire area of ​​the substrate.

[0011] It is therefore an object of the present invention to compensate or at least mitigate the disadvantages of prior art roll-to-plate imprinting apparatuses, while handling properties during the process - for example inserting substrates - and error rates should not be affected. Summary of the invention

[0012] This object is achieved by an embossing device for a roll-to-plate process, wherein the printing plate carrier has at least one cavity in which a substrate can be positioned and at least one side of the substrate is at least partially not surrounded by the cavity.

[0013] For a square form of the substrate, at least one side means that at least one side of the substrate is at least partially not surrounded by the cavity. If a square substrate is used, preferably two sides, most preferably two sides arranged opposite to each other, are not surrounded. Preferably, the unenclosed side or multiple unenclosed sides are in the imprinting direction. If a circular substrate is used, the substrate has only one side that is at least partially not surrounded by the cavity. The term "at least partially not surrounded / enclosed" means that at least 5%, more preferably at least 20% and most preferably at least 50% of the side is not surrounded by the cavity. For a square substrate, preferably 10%, more preferably 50% and most preferably 100% of one side is not surrounded by the cavity.

[0014] The term "not surrounded / enclosed" refers to the absence of cavity sidewalls. A cavity that is larger in size than the substrate, whereby a small gap exists between the cavity sidewalls and the substrate, thereby ensuring that the substrate is easily placed in the cavity, should not be understood as the term "not surrounded". This easily manipulable gap may have a width of tens to hundreds of microns.

[0015] Due to the fact that there is no cavity that completely encloses the substrate, the contact of the flexible master with the printing plate carrier and the substrate can remain constant during the imprinting process. If pressure is applied to the side of the roller to press the flexible master against the substrate, this pressure is distributed over the part (length) of the roller that is in contact with the substrate. This means that for example for a round substrate the pressure will be higher at the beginning and at the end. If a round substrate is arranged in a round cavity, the pressure will be evenly distributed over the substrate and the sides of the cavity. This is amplified if the sides of the cavity have the same height as the substrate and the total contact length of the roller on the substrate and the carrier plate is always the same.

[0016] However, the carrier plate does not need to be completely enclosed, but can have openings and can have various shapes compared to the form of the base plate. Thus, the form of the base plate becomes more independent of the form of the cavity, which is designed as described in the present invention.

[0017] Additionally, because the cavity does not completely surround the substrate, an outward flow is created. Excess uncured resin flows out during the imprint process and does not flow through the substrate.

[0018] In addition, since the substrate is not completely surrounded by the cavity, a channel leading to the substrate is formed. This channel can be used to reduce the oxygen inhibition of the acrylic resin, which causes the resin to not be fully cured. This oxygen inhibition will occur if the resin is exposed to oxygen while being cured by UV light. The resin will remain sticky on the surface, which is disadvantageous for handling and downstream process steps. The open area of ​​the cavity that creates the channel leading to the substrate can reduce this effect by injecting gas into the substrate, for example by replacing oxygen with nitrogen or other inert gases. Therefore, the substrate is surrounded by nitrogen injected through the channel, for example. In this case, the resin and the resin that is not completely trapped between the substrate and the flexible stamp during the curing step will be fully cured.

[0019] A further effect of the cavity is that along the roller, perpendicular to the embossing direction, the total length of the contact area of ​​roller, substrate and carrier plate is always equal and independent of the design of the substrate.

[0020] At least one substrate can be positioned in at least one cavity.If the substrate comprises more than one cavity, each cavity may comprise one or more substrates.

[0021] At least one cavity means that the printing plate carrier may comprise two or more cavities. However, in the following, the term "cavity" is used even if a plurality of cavities is included.

[0022] The printing plate carrier according to the invention is a plate comprising a carrier surface, wherein the area of ​​the carrier surface is larger than the thickness of the plate perpendicular to the carrier surface. The width and length of the printing plate carrier are larger than the area of ​​the substrate.

[0023] The substrate also has a substrate surface that is greater than the thickness of the substrate perpendicular to the substrate surface. The substrate has two substrate surfaces that are arranged in parallel and overlap each other. The substrate has a side surface that is perpendicular to the substrate surface. The curable varnish is present on one substrate surface.

[0024] The term "flexo-master" is used for any device that is flexible and suitable as a carrier for an embossed pattern. Preferably, the flexo-master is a flexible stamp or a flexible nickel pad.

[0025] The term "cavity" refers to any specific reduction or elevation of at least one section of a plate carrier, thereby forming a storage area for a substrate on the plate carrier. This includes, for example, a recess in the plate carrier comprising one or more side walls (see Figure 6b ) and a gap in the form of a groove in the printing plate carrier (see Figure 7). The storage area is part of the printing plate carrier and is the area on or in the printing plate carrier where the substrate is located.

[0026] Due to the at least one cavity, the roller with the flexo-master (and the reverse embossed pattern) is guided on the substrate while the roller and the edge of the flexo-master move on the printing plate carrier. Thus, the pressure of the flexo-master on the substrate is evenly distributed on the substrate.

[0027] It should be clear that there is a curable resin (also called lacquer) on top of the substrate surface (or on top of the flexible master), and the flexible master prints the structure into the lacquer, thereby forming a (reverse) embossed pattern on the substrate. When it is mentioned below that the flexible master is in contact with the substrate, this means that the reverse embossed pattern of the flexible master is transferred into the resin between the flexible stamp and the substrate. For other equipment devices of the embossing process and the embossing device, please refer to the document WO 2018 / 011208.

[0028] In a preferred embodiment, the cavity has a height approximately equal to the thickness of the substrate (see Figure 5 ). In a further preferred embodiment, the height of at least one cavity is approximately equal to the sum of the thickness of the substrate and the curable resin on the substrate. The term "equal to" means that the cavity height differs from the substrate thickness by less than 200 μm, preferably less than 100 μm, more preferably less than 50 μm, and most preferably less than 20 μm. For ease of understanding - during the imprinting process, the substrate has a propagation direction relative to the roller position and the thickness of the substrate is perpendicular to the propagation direction. For ease of understanding - this means that the substrate has a surface area to be imprinted and the thickness of the substrate is perpendicular to the imprinting surface. In this preferred embodiment, it is ensured that the surface of the flexible master is in contact with the upright sides of the substrate and the printing plate carrier, thereby generating a constant pressure on the substrate.

[0029] In a preferred embodiment, the cavity has one or more side walls and the height of the side walls is approximately equal to the sum of the thickness of the substrate and the thickness of the flexible master including the embossed pattern. Furthermore, in this embodiment, it is ensured that the flexible master with the reversed embossed pattern has at most the same width as the substrate, so as not to come into contact with the upright side of the printing plate carrier, thereby ensuring a constant pressure on the contact area. In a preferred embodiment, the width of the embossed pattern is smaller than the width of the cavity.

[0030] In both embodiments described above, full-surface contact with constant pressure over the contact area between substrate and flexible master significantly improves the imprinting result. As a result, a product of higher product quality is obtained with better controlled layer thickness uniformity.

[0031] In a preferred embodiment, the plate carrier comprises a compensation material. Preferably, the compensation material is an additional layer containing a fluid (such as a gas or liquid) or a flexible material. The plate carrier is preferably mainly made of a rigid material such as glass, whereby the additional compensation material is added.

[0032] The term "compensation material" refers to every material having reversible pressure compensation properties. In a preferred embodiment, the compensation material is a fluid. Preferably, the fluid is present in the form of an additional layer, which is in direct conformal contact with the plate carrier. The term "direct contact" means that the additional layer is in mechanical contact with the plate carrier. For example, the additional layer is placed between the substrate and the plate carrier. In a preferred embodiment, the fluid is a gas or a liquid. As a gas, the fluid is argon, nitrogen or air. Water, oil, acrylate fluid or curable acrylate fluid is a preferred liquid medium. In another preferred embodiment, the fluid is a viscoelastic fluid. Preferably, the plate carrier includes a fluid system, through which the fluid is poured into the additional layer (such as a pad for the substrate).

[0033] In another preferred embodiment, the compensating material is a flexible material. The term "flexible" means that the material can be reversibly compressed. The material can be easily bent without breaking. This means that the flexible material has elasticity compared to glass or metal. Preferably, the flexible material has a Young's modulus of 0.1 GPa to 10 GPa, more preferably a Young's modulus of 0.5 GPa to 5 GPa measured according to ASTM E111. For example, the flexible material can be rubber, elastomer, fiber material, EPDM, polychloroprene, polyurethane or other plastics or a mixture of the above materials.

[0034] In this application, a material is called rigid if it has a Young's modulus above 50 GPa measured according to ASTM E111.

[0035] In yet another preferred embodiment, the compensating material has a Shore value of less than 80 Shore A as measured according to ASTM D2240.

[0036] In a preferred embodiment, the plate carrier and the cavity are made in one piece. This means that the at least one cavity is part of the plate carrier and is produced by removing material of the plate carrier. An advantage of the one-piece embodiment is that no contaminants can collect in the seams of the plate carrier.

[0037] Preferably, the cavity is located in the compensation material. In this preferred embodiment, the cavity is a recess in the compensation material. In a preferred embodiment, the cavity is part of the compensation material. It is also preferred to place the compensation material, such as a flexible pad, in the cavity of the printing plate carrier. The flexible pad can extend beyond the cavity or be constrained by the cavity.

[0038] For this embodiment, the printing plate carrier may be made of a rigid material and the compensating material is a flexible pad.

[0039] In case of a fluid as compensation material, the substrate is placed on a gas bed or a liquid bed. Preferably, the plate carrier comprises a fluid flow system to create a gas bed or a liquid bed in the cavity, or the cavity itself comprises a fluid flow system. In both embodiments, the plate carrier can be present in a first plate carrier part and in a second plate carrier part.

[0040] In the roller-to-plate embossing process, large surfaces of the substrate can be embossed. These large surfaces can only be transported by using large plate carriers. The larger the plate carrier size, the more complicated it is to produce a flat surface of the plate carrier. If the plate carrier is not completely flat, the pressure on the substrate (which is located above the plate carrier) will be locally different. This will lead to local thickness variations in the finished product. In addition, if the back side of the (large) substrate (which is in contact with the plate carrier) is not uniformly flat due to thickness variations, defects or contamination (e.g. dust particles), pressure variations will also occur during embossing. In addition, non-uniformities of the embossing roller will also lead to pressure variations during embossing. All this will lead to locally thinner or thicker residual layer thicknesses. As a result, the non-uniform back side surface of the substrate is visible on the front side of the substrate - this is the lacquered side - and affects the quality of the embossed end product. Due to the use of compensation materials (e.g. flexible materials), the non-uniformities are compensated.

[0041] In yet another preferred embodiment, the plate carrier is made of at least two parts. Preferably, at least one of the two parts of the plate carrier is made of a compensating material or produces a compensating material. For example, the plate carrier can have a non-flexible material (glass) as a first part and a flexible material as a second part (as an embodiment of a compensating material). In another example, the first plate carrier part has a fluid flow system to produce an air bed or a liquid bed as a compensating material, and the second plate carrier part of the plate carrier is made of a rigid material or a flexible material forming a cavity. The cavity can be a part of the first part or the second part or extend on both parts. Preferably, the plate carrier is made of a first part of a glass or metal material, and the second plate carrier part is made of a flexible material, whereby the cavity is part of the second part. As an example, the cavity is completely embedded in the flexible material of the second plate carrier part of the plate carrier. In another example, the second plate carrier part contains a fluid flow system. The system is preferably located in the cavity. In addition, in this embodiment, the materials of the first and second plate carrier parts are the same or different. Due to the use of two parts, the two parts can be made of different materials, and even if the flexibility is increased, the stability of the plate carrier will not be reduced.

[0042] Preferably, the at least two parts of the plate carrier are reversibly connectable to each other. "Reversibly connectable" means that the two parts can be separated from each other without destroying either part. The connection between the two parts can be achieved via an adhesive surface on one or both parts, by glue and / or by a plug connection (such as a guide rail system or a locating pin) and / or via a screw system and / or magnetically or by a combination of the above systems. Due to the two-part structure of the plate carrier, it is easy to adapt the plate carrier to different substrate thicknesses (paint thicknesses) or flexible master thicknesses. In addition, by using a compensating material as a part, the part has a higher wear resistance than a part made of a non-flexible material. Therefore, only one part of the plate carrier (rather than the entire plate carrier) needs to be replaced.

[0043] Preferably, the flexible material is rubber or plastic foil. As an example, the flexible material can be rubber, elastomer, fiber material, EPDM, polychloroprene, polyurethane or other plastics or a mixture of the above materials.

[0044] In a preferred embodiment, the vacuum system is located in the cavity of the printing plate carrier. The cavity may have, for example, vacuum holes, through which a lower pressure can be generated in the cavity. This will keep the substrate in a defined position in the cavity, thereby improving the imprinting process. The vacuum holes are not comparable to fluid flow systems. The vacuum holes create a negative pressure (to keep the substrate in place), while the fluid flow system creates a fluid bed for the substrate.

[0045] In a further preferred embodiment, the printing plate carrier comprises a placement system. The placement system preferably comprises lifting fingers, by means of which the substrate can be easily placed on the carrier, for example by using a robot. In another preferred embodiment, the carrier comprises positioning pins (also called alignment pins or pushers) for positioning, by means of which the substrate can be placed in a preferred position, or always in the same position relative to a reference point. As a result, the process accuracy can be advantageously increased, because the imprinting process will always start at the same point of the substrate.

[0046] In a preferred embodiment, the cavity is the same form / shape as the substrate. In this context, "same form / shape" means, for example, that the cavity is not circular and that the substrate is angled. Preferably, one or more side walls of the cavity form a recess into which the substrate can be inserted. In this embodiment, the substrate is protected on a selected side of the substrate via the plate carrier during the imprinting process. The dimensions of the cavity can also be determined in such a way that the substrate is located in the plate carrier in a form-fitting manner, thereby avoiding sliding during the imprinting process. However, it is also conceivable that the cavity is formed as a wide groove extending over the entire carrier. Therefore, the cavity opening (the unenclosed portion of the substrate side) can be consistent with the imprinting direction or perpendicular to the imprinting direction. In addition, the two can be combined to form a square inner cavity.

[0047] In a further preferred embodiment, the cavity has convex sidewall ends. This means that the height of at least one sidewall end of the cavity increases at the end of the substrate. Due to this, the roller is lifted at the end of the embossing process, thereby reducing the embossing pressure and thereby preventing or reducing the overflow of the paint at the edge of the substrate. In a more preferred embodiment, the substrate has two convex sidewalls.

[0048] In yet another preferred embodiment, a foil is placed on top of the plate carrier and extends within the cavity. The substrate will be placed on the foil in the cavity. The foil protects the plate carrier and the cavity from contamination and / or prevents the substrate from sliding during the process and / or affects the reflective index of the substrate.

[0049] Additionally, further ideas relate to a roll-to-plate process, wherein a substrate is located within a cavity of a printing plate carrier and a flexible master having an inverted structure is pressed against the substrate, wherein the cavity height is adapted to match the height of the substrate and / or to match the heights of the flexible master and substrate, the substrate being located within the cavity in such a way that at least one substrate side is at least partially not surrounded by the cavity.

[0050] All embodiments mentioned for the embossing apparatus also apply to the roll-to-sheet process. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The concept of the present invention is further described below with reference to the accompanying drawings.

[0052] Figure 1 The embossing process is schematically shown.

[0053] Figure 2 The dependence of the measured imprint pressure on the layer thickness is shown.

[0054] Figure 3 One example of a varying substrate width that may result in a varying imprint pressure is schematically shown.

[0055] Figure 4 The imprint pressure at the center compared to the pressure at the edge of the substrate is schematically shown.

[0056] Figure 5 A printing plate carrier comprising cavities is schematically shown.

[0057] Figure 6 A printing plate carrier comprising cavities in the form of recesses is schematically shown.

[0058] Figure 6 B schematically shows a printing plate carrier comprising a cavity in the form of a recess having convex side wall ends.

[0059] Fig. 7A A printing plate carrier comprising circular cavities is schematically shown.

[0060] Figure 7B A printing plate carrier comprising two circular cavities is schematically shown.

[0061] Figure 8 A printing plate carrier comprising a first part and a second part is schematically shown.

[0062] Fig. 9 A printing plate carrier comprising a flexible material is schematically shown. DETAILED DESCRIPTION

[0063] Figure 1 The embossing arrangement and embossing process related to the present invention are shown. A flexible master 105 having an embossing pattern 105A with an inverted structure (negative) 105A required for the product is pressed onto a substrate 101 in a curable resin 102 by using a roller 104. The substrate 101 is a plate, for example but not limited to being made of rigid glass, and can have different shapes. The substrate 101 is placed on a printing plate carrier 100 to provide counter pressure and can be used for transportation. The printing plate carrier 100 can be made of glass or metal in particular. After curing the curable resin 102 (lacquer) by using UV light 107A from a UV light source 107, the flexible master 105 is removed and the cured resin 102 with the desired product texture 106B and the residual layer 106A below is transferred to the substrate 101.

[0064] The height of the curable resin 102 depends, among other things, on the imprint pressure. This height is the sum of the product texture 106B and the residual layer 106A. The residual layer 106A will have the same texture height regardless of the imprint pressure. The thickness of the residual layer 106B will decrease as the imprint pressure increases. This dependence is Figure 2 In addition to the imprint pressure, the residual layer thickness also depends on the imprint speed and the viscosity of the resin. Figure 2 In Figure 1, the correlation between printing pressure and layer thickness (residual layer and product texture) is shown for two different resin viscosities printed at a speed of 3.49 cm / min. Figure 2 It is shown that if the imprint pressure is increased from 10 N / cm to 20 N / cm, the layer thickness decreases from approximately 5.5 microns to 4 microns for a standard resin viscosity of 330 cP.

[0065] In the roller-to-plate imprinting process, the roller 104 is larger than the substrate, such as Figure 3 As shown. The embossing roller force Fr is applied on the sides (edges) of the roller 104. For a rigid roller, this total force is 2*Fr divided equally over the embossing contact surface. If the width of the substrate 101 is small, the line pressure (per unit or per centimeter) 108A will be higher compared to a wider substrate width resulting in a lower line pressure 108B. Due to this pressure variation on the substrate 101, the embossed pattern 105A of the flexible master 105 is not uniformly replicated into the lacquer on the substrate 101. The residual layer thickness may vary or even air bubbles may be trapped.

[0066] Figure 4 The changing imprint pressure at the edge of the substrate 101 at the end of the imprint process is shown. A similar problem occurs at the front of the substrate at the front of the imprint process. In both the starting and ending situations, the roller 104 presses the substrate 101 with a roller force Fr, with the flexible master 105 located in between. The roller 104 has a rigid core 104A and a softer, compressible outer layer 104B. Since the outer layer is soft, the roller 104 will be compressed due to the roller pressure and the roller contact surface 109A will be widened. This roller contact surface 109A on the substrate 101 will be smaller than the case where the roller 104 is pressed onto the roller contact surface 109B at the end of the substrate 101. In this case, the force remains the same, but will be performed on a smaller contact area of ​​the substrate 101. For a smaller roller contact surface 109A, the line pressure will increase, resulting in a lower residual layer thickness.

[0067] In order to account for the varying pressure at the front and rear ends of the substrate 101 and due to varying substrate widths, it is suggested that the printing plate carrier 100 contain cavities. Figure 5As shown in , the printing plate carrier 100 includes two raised side walls 112, thereby forming a cavity 110 in which the substrate 101 is located. Due to the upright carrier side walls, at the front end and / or end of the substrate 101, the pressure will be more evenly distributed when the roller transitions from the upright carrier side to the front end and / or end of the substrate 101 during the start and stop of the imprinting process. Therefore, the pressure will become uniform during the start and / or stop of the imprinting process. Note that having a raised side wall at the front or end of the substrate is beneficial for generating uniform pressure when the imprinting process starts or stops. Compared to the substrate thickness, the cavity height 110B preferably has a height difference of less than 200 microns, more preferably less than 100 microns and most preferably less than 50 microns. The cavity 110 does not completely surround the substrate 101. According to Figure 5 In an embodiment, the two sides of the substrate 101 are not enclosed by the cavity 110. The cavity 110 has an open area in which at least one side of the substrate 101 is at least partially not enclosed by the cavity 110. Therefore, it is more simplified to insert the substrate 101 into the cavity 110 or remove the substrate 101 from the cavity 110. Furthermore, the same cavity 110 can be used for square substrates with different widths without any quality reduction during the imprinting process. If the cavity 110 does not completely surround the substrate 101, the form of the cavity 110 becomes more independent. In one embodiment, the material of the raised side wall 112 and / or the printing plate carrier 100 is a compensating material. This can be a flexible material or a fluid material. In the case of a fluid material, the printing plate carrier 100 will preferably have an integrated air flow system or a liquid flow system.

[0068] In a more preferred embodiment, the raised sidewall 112 is removably (detachably) located on the substrate 101 and is designed to be connected to the substrate. The substrate 101 and the raised sidewall 112 together form a more uniform support.

[0069] Preferably, the substrate 101 is placed in parallel as close as possible to one or more side walls 112. Preferably, the substrate 101 directly contacts at least one side wall 112. If two side walls 112 are used, the cavity length preferably has the same length as the substrate 101, with a small surplus to enable the substrate 101 to be placed. This difference between the cavity length and the substrate length is preferably below 1 mm, more preferably below 500 microns, and most preferably below 200 microns. In each of these cases, the cavity length is longer than the substrate length.

[0070] The width of the roller 104 is generally greater than the width of the substrate 101. Figure 5 The cavity 110 shown in the two side walls 112 can also be rotated 90 degrees. Figure 6. Due to the upright sides 112 of the carrier 100, the imprint gap will be constant during the imprinting process. The length of the sidewall 112 is preferably longer than the length of the substrate 101, wherein the substrate 101 is preferably placed in the middle of the sidewall 112. The imprinting steps at the beginning and end of the substrate 101 will be greatly reduced. For a substrate 101 with a constant width, this will result in a uniform pressure over the entire imprinting area, including the beginning and end of the substrate 101. Note that due to the soft roller 104, there will be a small imprinting step. This small imprinting step can also be compensated by using the sidewall 112 at the front end and end of the substrate 101.

[0071] If the width of the flexible master 105 is greater than the width of the cavity 110, the cavity height 110B should be the same as the substrate thickness (substrate height), preferably with a variation of less than 200 microns, more preferably less than 100 microns, and most preferably less than 50 microns. If the width of the flexible master 105 is less than the width of the cavity 110 and is located within the cavity 110, the cavity height 110B should be the same as the sum of the thickness of the substrate 101 and the thickness of the flexible master 105.

[0072] Note that Figure 5 as well as Figure 6 and 6 In both imprinting processes shown in B, more substrates can be imprinted in the same imprinting cycle. If the cavity 110 is wide or long enough, multiple substrates can be placed on one side. In this case, the width of the roller 104 should be larger than the cavity 110. The flexible stamp should cover at least two substrates. The flexible stamp 105 can have multiple imprint patterns 105A aligned with the positions of the substrate 101. Or the flexible stamp can have one large imprint pattern 105A covering the substrate position 101.

[0073] Figure 6 B shows a similar imprinting arrangement. At the end of the imprinting process, typically near the end of the substrate 101, the height of an upright side wall end 113 placed at the side wall 112 of the printing plate carrier 100 increases with a ridge. Due to the ridge, the cavity height 110B will be higher. Due to this higher imprinting gap, the pressure will be reduced at the end of the imprinting process. Due to the low imprinting pressure at the end, resin overflow can be prevented. With such a ridge, it can be further ensured that overflow of resin will remain within the substrate surface and will not contaminate the printing plate carrier 100. The side wall end 113 does not necessarily have to be placed at the end of the side wall 112. The positioning depends on the position of the substrate 101 and the end of the imprinting process. Therefore, the side wall end 113 can also be placed in the middle of the printing plate carrier 110. The side wall end 113 can have different forms. Depending on Figure 6 B, the side wall ends have a wedge shape. However, a block form, a bridge form or a ski jump form are also preferred.

[0074] For substrates with varying widths, the pressure can be made uniform by adapting the cavity 110 to the shape of the substrate 101 . Fig. 7A An example is shown in FIG. 1 , which shows a circular cavity 110 suitable for imprinting on a circular substrate 101. In practice, the cavity 110 will be slightly wider to ensure easy loading and unloading in the printing plate carrier 100. The width margin is preferably less than 2 mm (1 mm on each side), more preferably less than 1 mm, and most preferably less than 400 microns. The cavity height 110B is the same as the substrate height. The cavity 110 comprises a groove, Fig. 7A In an embodiment of the present invention, the groove extends in the imprinting direction. Due to the groove, part of the circular substrate is not enclosed by the cavity 110. The groove can make it easy to load and unload the substrate. In addition, a liquid can flow along the groove and can support the substrate 101 during the imprinting process or support the manipulation component for inserting or removing the substrate 101.

[0075] Note that Fig. 7A A cavity is shown in FIG. 1 . However, it can also be Figure 7B By using a larger imprinting system and a larger flexible stamp, two or more substrates 101 can be imprinted in the same imprinting cycle. This increases the yield. In this case, the flexible stamp 105 should have multiple imprint patterns 105A and 105B. The positions of these imprint patterns 105A and 105B are aligned with the positions of the substrates 101 in the carrier 100. The flexible stamp 105 can also have one large imprint pattern covering the positions of the two substrates 101 on the carrier 100.

[0076] exist Figure 8 In the figure, a plate carrier 100 made of a first plate carrier part 100A and a second plate carrier part 100B is shown. The second plate carrier part 100B comprises a cavity 110. The first plate carrier part 100A and the second plate carrier part 100B can be reversibly connected to each other. Thus, a variable cavity height 110B can be produced, and the same base carrier material (first part 100A) can be used for different substrate heights. The material of the first plate carrier part 100A and the second plate carrier part 100B can be the same or different. For example, the material can be a glass or metal layer. The installation of the second plate carrier part 100B can be accomplished, for example, by using upright positioning pins on the first plate carrier part 100A and positioning holes on the second plate carrier part 100B.

[0077] In a preferred embodiment, Figure 8The printing plate carrier 100 in has a rigid first printing plate carrier part 100A and a flexible second printing plate carrier part 100B as a compensation material. For example, the second printing plate carrier part 100B can be made of a rubber or plastic sheet. If the back side of the substrate 101 is not uniformly flat due to defects or thickness variations, there will be pressure variations during imprinting. This will cause the thickness of the residual layer of resin 102 to be locally thinned. An uneven residual layer will be visible on the front side of the imprinted product. This effect can be avoided or mitigated by having a second printing plate carrier part 100B made of a flexible material. In the second example, the first printing plate carrier 100A has an integrated fluid flow system to generate an air bed by using an air flow system, or to generate a liquid bed by using a liquid flow system (compensation material). On the substrate 101 ( Figure 8 An air or liquid cushion underneath (not shown) serves as a non-uniformity compensation layer.

[0078] exist Fig. 9 In the embodiment, the printing plate carrier 100 includes a cavity 110, wherein a flexible material 111 as an example of a compensation material is located inside the cavity 110 and on the upper side of the printing plate carrier 100. Due to the use of the flexible material 111, the influence of pressure variation and the consequent imprint variation caused by defects or uneven layer thickness under the substrate 100 can be avoided or mitigated.

Claims

1. An embossing device for a roll-to-plate process, comprising a flexible master (105), a printing plate carrier (100) and a substrate (101), wherein the flexible master (105) can be pressed against the substrate (101) during the embossing process and the printing plate carrier (100) comprises at least one substrate (101), wherein the printing plate carrier (100) has at least one cavity (110), wherein the at least one substrate (101) is located in the cavity (110), It is characterized in that At least one substrate side surface is at least partially not surrounded by the cavity (110), wherein not being surrounded by the cavity means that at least a portion of the cavity sidewall does not exist.

2. The imprinting device according to claim 1, in, The height (110A) of the at least one cavity (110) is equal to the sum of the thickness of the substrate (101) and the thickness of the curable resin (102) on the substrate (101).

3. The imprinting device according to claim 1, in, The height (110A) of the at least one cavity (110) is equal to or less than the sum of the thickness of the substrate and the thickness of the flexible master (105).

4. The embossing device according to any one of claims 1 to 3, in, The printing plate carrier (100) comprises a compensation material (111).

5. The imprinting device according to claim 4, in, The cavity (110) is located within the compensation material (111), or the compensation material (111) is located in the at least one cavity.

6. The embossing device according to any one of claims 1 to 3, in, The printing plate carrier (100) and the cavity (110) are manufactured in one piece.

7. The embossing device according to any one of claims 1 to 3, in, The printing plate carrier (100) consists of at least two parts (100A, 100B).

8. The imprinting device according to claim 7, in, The at least two parts (100A, 100B) of the printing plate carrier (100) can be reversibly connected to one another.

9. The imprinting device according to claim 7, in, At least one of the two parts (100A, 100B) of the printing plate carrier (100) is made of a compensation material (111).

10. The imprinting device according to claim 4, in, The compensating material is a flexible material (111), wherein the flexible material has a Young's modulus between 0.1 GPa and 10 GPa measured according to ASTM E111.

11. The imprinting device according to claim 10, in, The flexible material has a Young's modulus between 0.5 GigaPascal (GPa) and 5 GigaPascal (GPa) measured according to ASTM E111.

12. The embossing device according to any one of claims 1 to 3, in, A fluid flow system is located within the cavity (110) of the printing plate carrier (100).

13. The embossing device according to any one of claims 1 to 3, in, The printing plate carrier (100) comprises a placement system for the substrate (101).

14. The embossing device according to any one of claims 1 to 3, in, The form of the cavity (110) is the same as that of the substrate (101).

15. The embossing device according to any one of claims 1 to 3, in, The substrate (101) and / or the printing plate carrier (100) has at least one raised side wall (112), wherein the at least one raised side wall (112) has a raised side wall end (113).

16. A roll-to-plate process, wherein a substrate (101) is located in a cavity (110) of a printing plate carrier (100) and a flexible master (105) is pressed onto the substrate (101), wherein the height (110B) of the cavity is adapted to match the height of the substrate (101) and / or to match a combination of the height of the flexible master (105) and the height of the substrate, wherein the substrate (101) is located in the cavity (110) in such a way that at least one substrate side of the substrate is at least partially not surrounded by the cavity (110), wherein not being surrounded by the cavity means that at least a portion of the cavity side wall does not exist.

Images